1. Field of the Invention
This invention relates to an apparatus for and method of scoring a piece of refractory material, e.g., glass using a scoring wheel having an arcuate scoring surface.
2. Discussion of the Prior Art
In general, prior art scoring wheels for scoring refractory material, e.g., glass, ceramics, or glass-ceramics prior to severing have a scoring angle of from about 130.degree. to about 180.degree.. One of the problems associated with this type of scoring wheel is that varying degree of wing and/or spall are present at the cut edges of the glass. Normally the wing and/or spall is removed by grinding or polishing to increase the edge strength of the piece of glass. As can be appreciated by those skilled in the art, wing and/or spall are localized areas of flaws which, if not removed, generate cracks in the piece of glass.
In each of U.S. Pat. Nos. 3,865,294 and 3,865,673, there is taught a method of employing scoring wheels having a cutting angle to produce cut edges on a piece of glass that are essentially free of wing and/or spall. The cut edges of the glass piece produced in accordance to the teachings of the above-identified patents are smooth, strong, straight, pristine and perpendicular to the major surfaces of the glass.
One of the variables in the scoring methods of the above-identified patents is wheel speed. As can be appreciated eliminating scoring wheel speed as a scoring variable yields a scoring method that is easier to control.
It would be advantageous if another glass scoring method was available that produces cut edges on a piece of glass that are essentially free of wing and/or spall, smooth, strong, straight, pristine, perpendicular to the major surfaces, and avoids the need for grinding and polishing. Further, it would be advantageous if the scoring method did not have scoring wheel speed as a variable.